Compression sensitive suspension dampening

ABSTRACT

A spring for a suspension is described. The spring includes: a spring chamber divided into at least a primary portion and a secondary portion, and a fluid flow path coupled with and between the primary portion and the secondary portion. The fluid flow path includes a bypass mechanism, wherein the bypass mechanism is configured for automatically providing resistance within the fluid flow path in response to a compressed condition of the suspension.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims priority toand benefit of co-pending U.S. patent application Ser. No. 16/937,482filed on Jul. 23, 2020 entitled “COMPRESSION SENSITIVE SUSPENSIONDAMPENING” by Sante Pelot, having Attorney Docket No.FOX-P2-25-11-US.CON4, assigned to the assignee of the presentapplication, and incorporated herein, in its entirety, by reference.

The U.S. application Ser. No. 16/937,482 is a continuation applicationof and claims priority to and benefit of U.S. patent application Ser.No. 15/393,939 filed on Dec. 29, 2016, now Issued U.S. Pat. No.10,723,408, entitled “COMPRESSION SENSITIVE SUSPENSION DAMPENING” bySante Pelot, having Attorney Docket No. FOX-P2-25-11-US.CON3, assignedto the assignee of the present application, and incorporated herein, inits entirety, by reference.

The U.S. Ser. No. 15/393,939 application is a continuation applicationof and claims priority to and benefit of U.S. patent application Ser.No. 14/981,274 filed on Dec. 28, 2015, now Issued U.S. Pat. No.9,533,732, entitled “COMPRESSION SENSITIVE SUSPENSION DAMPENING” bySante Pelot, having Attorney Docket No. FOX-P2-25-11-US.CON2, assignedto the assignee of the present application, and incorporated herein, inits entirety, by reference.

The U.S. application Ser. No. 14/981,274 is a continuation applicationof and claims priority to and benefit of U.S. patent application Ser.No. 14/270,273, now U.S. Pat. No. 9,254,887, filed on May 5, 2014entitled “COMPRESSION SENSITIVE SUSPENSION DAMPENING” by Sante Pelot,having Attorney Docket No. FOX-P2-25-11-US.CON, assigned to the assigneeof the present application, and incorporated herein, in its entirety, byreference.

The U.S. application Ser. No. 14/270,273 is a continuation applicationof and claims priority to and benefit of U.S. patent application Ser.No. 13/404,916, now U.S. Pat. No. 8,800,973, filed on Feb. 24, 2012entitled “COMPRESSION SENSITIVE SUSPENSION DAMPENING” by Sante Pelot,having Attorney Docket No. FOX-P2-25-11-US, assigned to the assignee ofthe present application, and incorporated herein, in its entirety, byreference.

The application U.S. Ser. No. 13/404,916 claims priority to and benefitof U.S. provisional patent application 61/446,927, filed Feb. 25, 2011entitled “METHODS AND APPARATUS FOR COMPRESSION SENSITIVE SUSPENSIONDAMPENING”, by Sante Pelot, having Attorney Docket No. FOX-P2-25-11-PRO,assigned to the assignee of the present application, and is incorporatedherein, in its entirety, by reference.

FIELD OF THE INVENTION

Embodiments generally relate to methods and apparatus for use in vehiclesuspension. Particular embodiments relate to methods and apparatususeful for variable and position sensitive dampening rate in vehicleshock absorbers. More particular embodiments relate to methods andapparatus useful for variable and position sensitive dampening rate invehicle front forks.

BACKGROUND

Vehicle suspension systems typically include a spring component orcomponents and a dampening component or components. Typically,mechanical springs, such as helical springs are used with some type ofviscous fluid-based dampening mechanism and the two are mountedfunctionally in parallel. In its basic form, the damper controls thespeed of movement, such as telescopic compression, of the suspension bymetering substantially incompressible fluid from one side of a piston tothe other, and/or from a main chamber to a reservoir, during acompression stroke.

While various refinements have been made to shock absorbers to enhancetheir performance, one continuing problem is that of a “bottom out”condition due to high compressive forces brought about by terrain andthe weight of a rider. What is needed is a bottom out buffering systemthat provides a complete and user-adjustable secondary cushionarrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an “asymmetric” bicycle fork having a damping leg anda spring leg, in accordance with an embodiment.

FIG. 2 is an enlarged view of a structure of the spring leg illustratedin FIG. 1 , in accordance with an embodiment.

FIG. 3 is an enlarged view of a structure of the spring leg illustratedin FIG. 1 , in accordance with an embodiment.

FIG. 4 is an enlarged view of a structure of the spring leg illustratedin FIG. 1 , in accordance with an embodiment.

FIG. 5 illustrates an “asymmetric” inverted bicycle fork having adamping leg and a spring leg, in accordance with an embodiment.

FIG. 6 is an enlarged view of a structure of the spring leg illustratedin FIG. 5 , in accordance with an embodiment.

FIG. 7 is an enlarged view of a structure of the spring leg illustratedin FIG. 5 , in accordance with an embodiment.

The drawings referred to in this description should not be understood asbeing drawn to scale unless specifically noted.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings. While the technology willbe described in conjunction with various embodiment(s), it will beunderstood that they are not intended to be limited to theseembodiments. On the contrary, the present technology is intended tocover alternatives, modifications and equivalents, which may be includedwithin the spirit and scope of the various embodiments as defined by theappended claims.

Furthermore, in the following detailed description, numerous specificdetails are set forth in order to provide a thorough understanding ofembodiments. However, embodiments may be practiced without thesespecific details. In other instances, well known methods, procedures,components, and circuits have not been described in detail as not tounnecessarily obscure aspects of embodiments.

The discussion that follows will describe the structure andfunctionality of embodiments.

FIG. 1 shows an “asymmetric” bicycle fork 100 having a damping leg A anda spring leg B. The damping leg A includes an upper leg tube 105 mountedin telescopic engagement with a lower leg tube 110 and having fluiddamping components therein. The spring leg B includes an upper leg tube106 mounted in telescopic engagement with a lower leg tube 111 andhaving spring components therein. In one embodiment, the spring leg Bincludes a spring chamber 185. The spring chamber 185 is divided into aprimary portion 190 and a secondary portion 195. In one embodiment, theprimary portion 190 includes at least a portion of the upper leg tube106 and the secondary portion 195 includes at least a portion of thelower leg tube 111. The lower leg tube 111 includes the air springchamber 112, as shown. Further, a seal 114 is positioned at the upperend of the lower leg tube 111 and between the outer surface of the lowerleg tube 111 and the upper leg tube 106. The seal 114 assists indefining the volume of fluid in the oil bath chamber 125.

FIG. 2 is an enlarged view of a structure of the spring leg Billustrated in FIG. 1 , according to an embodiment. With reference toFIGS. 1 and 2 , in one embodiment, the spring components of spring leg Binclude a helically wound spring 115 and the structure of portion “C” asshown further in FIG. 2 . The helically wound spring 115 is containedwithin the upper leg tube 106 and axially restrained between the top cap200 and the flange 165. The flange 165 is disposed at an upper end ofthe riser tube 135 and fixed thereto. The lower end of the riser tube135 is connected to the lower leg tube 111 and fixed relative thereto.

A fluid flow path 160 includes a bypass mechanism that automaticallyprovides resistance within the fluid flow path 160 in response to acompressed condition of the suspension. In one embodiment, the bypassmechanism is a valve 152. The valve 152, in one embodiment, includes avalve plate 155. The valve plate 155 is positioned within the upper legtube 106 and axially fixed thereto such that the plate 155 moves withthe upper tube 106. The valve plate 155 is annular in configuration,surrounds the exterior surface of the riser tube 135 and is axiallyslidable in relation thereto. The valve 152 includes an outer seal 151on an outer surface where such outer seal 151 seals between an interiorsurface of the upper leg tube 106 and an exterior surface of the valveplate 155, thereby isolating spring chamber 170 from oil bath chamber125. The valve plate 155 further includes an inner seal 150 about aninterior surface thereof, where such inner seal 150 dynamically sealsbetween the interior surface of the valve plate 155 and an exteriorsurface of the riser tube 135.

Of note, while the bypass mechanism is shown as a valve 152 in oneembodiment, it should be appreciated that any type of mechanism thatcauses resistance to the flow of fluid within the fluid flow path 160may be used. For example, but not limited to such example, a narrowingbeveled portion of the fluid flow path 160 could function as a bypassmechanism. For example, the narrowed beveled portion of the fluid flowpath 160 may be smaller in diameter than that of the piston 187 movingthere through. Thus, the piston 187, upon interaction with the narrowedbeveled portion of the fluid flow path 160 will at least slow due to aninterference fitting, if not stop completely. This will result in abuffering of the bottom out effect. FIG. 2 also shows a seal 114, whichalso assists in defining the volume 125 of fluid in the oil bath chamber125.

In yet another embodiment, FIG. 4 illustrates an enlarged view of thestructure C of FIG. 1 , in accordance with an embodiment. With referencenow to FIGS. 1, 2 and 4 , in one embodiment, the bypass mechanism is atapered outer diameter 405 on the riser tube 135. The tapered outerdiameter 405 is configured for providing resistance to a compressingmovement of said suspension. For example, as the valve 152 is pusheddownwards towards the tapered outer diameter 405 of the riser tube 135,over the narrowed section 410 and onto the widened section 415, adynamic seal 425 of the valve 152 engages with the widened section 415of the outer diameter, at about, but not limited to, area 420. The valve152, therefore, encounters resistance through the sealing of the lowerair spring chamber 112. The volume of fluid within oil bath chamber 125is reduced when the dynamic seal 425 engages the widened section 415 ofthe riser tube 135 at area 420. It should be appreciated that thedynamic seal 425 is coupled with the valve 152 and is the closestcomponent of the valve 152 to the outer surface of the riser tube 135.

Of note, the use of the tapered outer diameter 405 avoids the dynamicseal friction occurring at the top of a stroke, as compared to theembodiment with the at least one aperture 145 (as will be discussedherein). Essentially, the use of the tapered outer diameter 405 of theriser tube 135 enables the benefits of a coil (low friction) and an airspring (progressivity) to both be realized.

In one embodiment, a spring for a suspension includes the spring chamber170 and a fluid flow path 160 coupled with and between the primaryportion 190 and the secondary portion 195.

In one embodiment, an oil bath chamber 125 of the spring leg B containsa substantially incompressible lubricant (e.g. oil) having an uppersurface level 130. Spring chamber 170, fluid flow path 160 and an upperportion 125 a of oil bath chamber 125 contain a compressible fluid suchas, for example, atmospheric air (with the fork in a fully extendedstate). FIG. 3 illustrates an enlarged view of a structure of the springleg illustrated in FIG. 1 , in accordance with an embodiment. Withreference now to FIGS. 1-3 , the riser tube 135 includes at least oneaperture 145 through a wall thereof that communicates an exterior (e.g.upper portion 125 a) of the riser tube 135 with an interior 140 of theriser tube 135. In one embodiment, an interior 140 of the riser tube 135contains, at least in part, a compressible fluid (e.g. gas, air). In oneembodiment, the upper leg tube 106 is held centralized within the lowerleg tube 111 by an annular bushing 120.

Reference directions “down” 175 and “up” 180 are shown in FIG. 1 . Inoperation, the lower leg tube 111 moves up relative to the upper legtube 106 (and/or the upper leg tube 106 moves down relative to the lowerleg tube 111) when an obstruction is encountered by a vehicle equippedwith the symmetric bicycle fork 100. During such compression, the upperleg tube 106 is extended telescopically further into the lower leg tube111 and the helically wound spring 115 is compressed axially between thetop cap 200 (fixed to the upper leg tube 106) and the flange 165 (fixedto the lower leg tube 111 via the riser tube 135). In addition to thehelically wound spring 115, gas within the spring leg B is compressed asthe interior volume (formed by the combined interiors of the upper legtube 106 and the lower leg tube 111) decreases with compression. In oneembodiment, the gas within the interior of the spring chamber 170, fluidflow path 160, and the upper portion 125 a of the oil bath chamber 125is initially atmospheric air and the volumes of the spring chamber 170and the fluid flow path 160 are in fluid communication with the volumeof the upper portion 125 a of the oil bath chamber 125 via the at leastone aperture 145 so that compression of the atmospheric air has littlespring effect.

In one embodiment, the valve plate 155 moves downward, with the upperleg tube 106 and relative to an exterior of the riser tube 135 and hencethe at least one aperture 145. Based on the design position of the atleast one aperture 145 and the other design factors, the valve plate 155passes downward over the at least one aperture 145 at some compressivestate of the spring leg B prior to complete bottom out (“bottom out”refers to a point of maximum practical leg compression). When the valveplate 155 and the inner seal 150 pass downward over the at least oneaperture 145, the fluid communication between the spring chamber 170 andthe fluid flow path 160 and the upper portion 125 a of the oil bathchamber 125 is closed. Further movement downward (relative to the lowerleg tube 111 and the riser tube 135) of the valve plate 155 and theupper leg tube 106 acts to further compress a relatively small volume ofgas contained in the upper portion 125 a of the oil bath chamber 125.Because the volume in the upper portion 125 a of the oil bath chamber125 is small, further compression of that upper portion 125 a of the oilbath chamber 125 results in the rapid build-up of pressure within theupper portion 125 a of the oil bath chamber 125 which acts axially overthe piston area of the valve plate 155 and greatly augments the springforce in the spring leg B previously (i.e., before closure of the atleast one aperture 145) supplied only by the helically wound spring 115.In one embodiment, the upper surface level 130 of the oil in the oilbath chamber 125 may be adjusted upwardly or downwardly to increase ordecrease, respectively, a pressure rise rate of the upper portion 125 aof the oil bath chamber 125 following the closure of the at least oneaperture 145. Additionally, the system may be pressurized from the topcap 200 or the base stud. For example, the upper portion 125 a (e.g.,air chamber) of the oil bath chamber 125 may be pressurized, in order toassist in the resistance to the compressive forces. It should beappreciated that various embodiments may not include the at least oneaperture 145.

Of note, in one embodiment and as discussed herein, the valve 152includes an inner seal 50 disposed on an interior surface of the valveplate 155. The inner seal 50 dynamically seals between the interiorsurface of the valve plate 155 and an exterior surface of the riser tube135. By “dynamically”, it is meant that the inner seal 50 accomplishesthe sealing during the process movement of the valve. Further, in oneembodiment and as discussed herein, the valve 152 includes an outer seal51 disposed on an outer surface of the valve plate 155. The outer seal51 seals between an interior surface of the primary portion 190 and theouter surface of the valve plate 155 such that the primary portion 190is isolated from the oil bath chamber 125. The oil bath chamber 125 ispositioned below the primary portion 190. As discussed herein, the oilbath chamber 125 is configured to hold a fluid.

In practice, one embodiment of the spring leg B of the symmetric bicyclefork 100 exhibits a smooth and predictable compression spring rate basedon a helically wound spring 115 until and/or unless a large compressiveforce is encountered. If such force is imparted to the fork, thesymmetric bicycle fork 100 will compress predictably until near (as nearas desired based on design and fluid level selection) bottom out atwhich point the effective spring rate of the symmetric bicycle fork 100will increase rapidly due to the added relatively small volume and highspring rate of the gas spring. Such a rapid late compression increasewill help the symmetric bicycle fork 100 avoid bottom out and itsassociated jarring effects on the vehicle and the operator.

FIG. 5 illustrates an “asymmetric” inverted bicycle fork having adamping leg E and a spring leg F, in accordance with an embodiment. Alsoof note, FIG. 5 illustrates a spring chamber 505 within the spring legF. The spring chamber 505 includes a lower bushing 510 and a seal 515within the spring chamber 505. The seals 515 and 605 (of FIG. 6 ) assistin defining the volume of fluid in the oil bath chamber 705 (of FIG. 7). FIG. 6 illustrates an enlarged view of a structure D of the springleg F illustrated in FIG. 5 , in accordance with an embodiment. FIG. 7illustrates an enlarged view of the structure D of the spring leg Fillustrated in FIGS. 5 and 6 , in accordance with an embodiment.

With reference now to FIGS. 1-7 , in one embodiment, the spring includesa spring chamber 505 divided into at least the primary portion 190 andthe secondary portion 195. The spring further includes a combination ofa compressible fluid and an incompressible fluid. This combination isconfigured for automatically providing resistance in response to acompressed condition of the suspension. For example, but not limited tosuch example, in general terms, the combination provides resistance tothe movement of the upper and lower leg tubes relative to each other,thereby reducing and/or avoiding the bottom out effect.

As illustrated in FIG. 7 and denoted in regions containing squigglelines, in one embodiment the primary portion 190 contains at least avolume of one or more fluids. Moreover, as denoted in regions containingdots, in one embodiment the secondary portion 195 contains at least avolume of one or more fluids. As further illustrated in FIG. 7 , thespring chamber 505 includes an oil bath chamber 705 containing a volumeof compressible and incompressible fluid, a dynamic seal 710, a piston715, a slider 720, and an upper bushing 725. Of note, there is no fluidflow path between the primary portion 190 and the secondary portion 195.The dynamic seal 710 is always engaged at any position within the fork'stravel, such that a resistance is always provided to reduce and/or avoidthe bottom out effect. In other words, the primary portion 190 and thesecondary portion 195 are sealed from each other 100% of the time. Theresistance to the bottom out effect results at least partially from thecompression of the compressible fluid volume with the oil bath chamber705 during the fork's travel.

The slider 720 functions, at least in part, analogously to the upper legtube 106 shown in FIGS. 1-4 . The slider 720 “slides” within the upperleg tube 730. In general terms, the movement of the slider 720 into theupper leg tube 730 causes the compressible fluid within the oil bathchamber 705 to become compressed, and forces the oil (incompressiblefluid) from the oil bath chamber 705 to travel around the secondarychamber 195 to the upper and lower bushings, 725 and 510 (shown in FIG.5 and not shown in enlarged FIG. 7 ), respectively. (Of note, the upperand lower bushings, 725 and 510, respectively, are slotted so that theypermit fluid to bypass them.) Thus, upon compression, the upper andlower bushings, 725 and 510, respectively, automatically receivelubrication via an oil bath. In this manner, the embodiments shown inFIGS. 5-7 enable a reduced volume of oil to be used within a vehiclecompared to conventional designs, while enabling a more efficientlubrication method and a lighter vehicle design.

Thus, the combination of the compressible and incompressible fluidsprovides a resistance to the movement of at least the piston 715,thereby avoiding or mitigating the bottom out effect. Of note, theembodiments shown in FIGS. 5-7 may be used in a motorcycle. Thisembodiment may reduce the overall expected weight of the motorcycle byreducing the overall oil needed (as well as forcing the oil into abushing area where it is needed for lubrication). However, it should beappreciated that embodiments shown in FIGS. 1-4 also may be integratedwith the embodiments shown in FIGS. 5-7 .

With reference again to FIGS. 1 and 2 , in one embodiment, a vehiclesuspension includes: a gas chamber having a first portion 190 and asecond portion 195; a gas flow by-pass, having an open conditionallowing a gas flow between the first portion and the second portion,and having a closed condition substantially denying the gas flow; and afirst telescopic member and a second telescopic member (e.g., upper legtube and/or lower leg tube, 106 and 111, respectively) being slidablyengaged and having a relatively extended position wherein the gas flowby-pass is in the open condition, and a relatively compressed positionwherein the gas flow by-pass is in the closed condition.

In operation, in one embodiment, the suspension is compressed to apredetermined location. A substantially sealed relationship between aprimary portion of a spring chamber and a secondary portion of thespring chamber is created. A spring rate of the suspension is changed inresponse to the creation of the substantially sealed relationship.

In one embodiment, an upper surface level of oil in the oil bath chamberdisposed within the secondary portion is adjusted upwardly to increase apressure rise rate of the spring chamber following the creation of thesubstantially sealed relationship. In another embodiment, the uppersurface level of oil in the oil bath chamber disposed within thesecondary portion is adjusted downwardly to decrease a pressure riserate of the spring chamber following the creating of the substantiallysealed relationship.

In one embodiment, the compressing of the suspension to a predeterminedlocation includes: extending the primary portion telescopically furtherinto the secondary portion, wherein the primary portion is at leastpartially and telescopically positioned within the secondary portion;compressing a helically wound spring between a top cap that is coupledwith the primary portion and a flange that is coupled with the secondaryportion; and decreasing an interior volume of combined interiors of theprimary portion and the secondary portion as the helically wound springis compressed, wherein a gas within the spring chamber is compressedconcurrently with the decreasing of the interior volume.

In one embodiment, the creating of a substantially sealed relationshipincludes: automatically closing a valve of a fluid flow path in responseto a compressed condition of the suspension to create the substantiallysealed relationship, wherein the fluid flow path is coupled with andbetween the primary portion and the secondary portion. In oneembodiment, the automatically closing the valve of the fluid flow pathincludes: moving a valve plate of the valve downward with a movement ofthe primary portion, the valve plate being coupled with the primaryportion, being annular, and surrounding an exterior surface of a risertube and is axially slidable in relation to the riser tube, wherein themoving the valve plate downward is relative to the exterior of a risertube, wherein the riser tube is disposed within and between the primaryportion and the secondary portion, contains a compressible fluid and atleast one aperture, the at least one aperture being configured forenabling fluid communication between the exterior and an interior of theriser tube. In one embodiment, the automatically closing of the valve ofthe fluid flow path further includes: moving the valve plate downwardswith the movement of the primary portion to cover the at least oneaperture such that the sealed relationship is formed and a fluidcommunication between an interior and an exterior of the riser tube isclosed. In one embodiment, the moving of the valve plate downwards withthe movement of the primary portion to cover the at least one apertureincludes: moving the valve plate downwards to cover the at least oneaperture such that the sealed relationship is formed prior to abottoming out. In one embodiment, the primary portion and the valveplate is moved telescopically further downward to further compress arelatively small volume of gas contained in an upper portion of an oilbath chamber, such that a rapid build-up of pressure within the upperportion of the oil bath chamber occurs which acts axially over a pistonarea of the valve plate and augments a spring force in a spring in thespring chamber.

In one embodiment, the moving of the valve plate downwards includes:sealing, by an outer seal disposed on an outer surface of the valveplate, such that the primary portion is isolated from an oil bathchamber that is positioned below and coupled with the primary portion,wherein the oil bath chamber is configured for holding fluid. In anotherembodiment, the moving of the valve plate downwards includes:dynamically sealing, by an inner seal disposed on an interior surface ofthe valve plate, between an interior surface of the valve plate and anexterior surface of the riser tube.

In operation, in another embodiment, a method for operating asuspension, includes: compressing said suspension; receiving saidcompressing by a combination of a compressible fluid and anincompressible fluid; and automatically providing resistance by saidcombination in response to a compressed condition of said suspension.

Thus, embodiments provide a gas/spring cushion that mitigates the“bottom-out” effect.

While the foregoing is directed to certain embodiments, other andfurther embodiments may be implemented without departing from the scopeof the present technology, and the scope thereof is determined by theclaims that follow.

What we claim is:
 1. A component for a vehicle suspension, saidcomponent comprising: an upper leg tube; a lower leg tube telescopicallycoupled to said upper leg tube; a spring disposed in at least one ofsaid upper leg tube and said lower leg tube and configured to provide aspring force which resists telescopic compression of said upper leg tubeand said lower leg tube; a first fluid chamber containing a first fluid,said first fluid chamber containing at least said spring, wherein saidlower leg tube at least partially defines said first fluid chamber; asecond fluid chamber containing a second fluid, said second fluidchamber being disposed at least partially around said first fluidchamber; and a dynamic seal positioned to separate said first fluidchamber from said second fluid chamber.